Eastern Arborvitae
Thuja occidentalis
Eastern Arborvitae (Thuja occidentalis) is a tree suited to the Colorado Front Range, rated "Recommended for Most Sites" on the 2024 Front Range Tree Recommendation List. It matures to about 12 to 30 ft tall and 4 to 8 ft wide, needs medium to high water, and prefers full sun to partial shade. Needs protected area; susceptible to winter burn.
medium to high water12 to 30 ft tall and 4 to 8 ft wide
Photos
- Photo 1: (c) Tom Norton, some rights reserved (CC BY)
- Photo 2: "Podlaskie - Suprasl - Kopna Gora - Arboretum - Thuja occidentalis 'Smaragd' - plant" by Athantor is licensed under CC BY-SA 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/4.0/.
- Photo 3: "Thuja occidentalis - tree (aka)" by André Karwath aka Aka is licensed under CC BY-SA 2.5. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/2.5/.
- Photo 4: "Thuja occidentalis 'Sherwood Frost' 2014" by F. D. Richards is licensed under CC BY-SA 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/2.0/.
- Photo 5: "Thuja occidentalis 'Globosa Aurea', Golden Globe Arborvitae or Tuya Golden Globe" by F. D. Richards is licensed under CC BY-SA 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/2.0/.
- Photo 6: no rights reserved
At a glance
Will it survive here?
- Hardiness zones
- USDA 2 to 8
- Water needs
- medium to high water
- Sun
- Best in full sun; tolerates partial shade.
- Soil
- clay, loam
- Soil pH
- 6.0 to 8.2
- Hail tolerance
- high
- Wind tolerance
- high
- Salt tolerance
- moderate
How big, what shape?
- Mature size
- 12 to 30 ft tall and 4 to 8 ft wide
- Mature form
- Pyramidal
- Spacing / clearance
- ~8 ft of clearance
- Growth rate
- Moderate
- Lifespan
- Long-lived
What it looks like, and when
- Foliage
- Evergreen
Who else benefits
- Pollinator value
- low
- Deer
- Not rated
- Colorado native
- No
Also worth knowing
- Fire rating
- Ignitable (CSU): keep 30+ ft from the house, thinned
Site factors to consider
- Critical: Cold HardinessThe average low suits it fine; our real cold risk is the swings, late frosts, and intense winter sun, so wrap young trunks and give it shelter.
- Watch: Leaf ScorchIts leaf edges brown in hot, dry wind, so give it steady summer water and some shelter from the worst afternoon blast.
Frequently asked questions
- Is Eastern Arborvitae good for the Colorado Front Range?
- Yes, Eastern Arborvitae is a well-suited tree for Colorado's Front Range, rated "Recommended for Most Sites" on the 2024 Front Range Tree Recommendation List.
- How big does Eastern Arborvitae get?
- It matures to about 12 to 30 ft tall and 4 to 8 ft wide.
- How much room does Eastern Arborvitae need?
- Give Eastern Arborvitae about 8 ft of clearance from buildings, fences, and other trees so the mature canopy isn't crowded.
- What shape does Eastern Arborvitae grow into?
- Eastern Arborvitae typically grows into a pyramidal, conical outline that is widest at the base. This is the species' usual mature form, named cultivars (columnar, weeping, or compact selections) can differ, so check the specific cultivar.
- Is Eastern Arborvitae hardy on the Front Range?
- Eastern Arborvitae is hardy in USDA 2 to 8. The Colorado Front Range spans roughly USDA 4b to 6a, so it is well within range. That said, it carries a cold-hardiness caution: The average low suits it fine; our real cold risk is the swings, late frosts, and intense winter sun, so wrap young trunks and give it shelter.
- How much water does Eastern Arborvitae need?
- It needs medium to high water once established.
- How fast does Eastern Arborvitae grow?
- Eastern Arborvitae is a moderate-growing tree. Growth rate depends on water and site conditions on the Front Range.
- How long does Eastern Arborvitae live?
- Eastern Arborvitae is long-lived, a multi-generational tree given good siting and care. Actual lifespan varies with site, water, and care.
- Is Eastern Arborvitae native to Colorado?
- No. It is not a Colorado native, but it grows well on the Front Range.
- Is Eastern Arborvitae a good firewise plant near the house?
- Eastern Arborvitae is an evergreen conifer, and CSU Extension notes conifers tend to be ignitable because of their oil and pitch, even when well watered, so keep it 30 or more feet from the house and keep it thinned and well maintained. This is general guidance based on CSU Extension Fact Sheet 6.305 (2025), not a guarantee that any plant won't burn, a well-irrigated, well-maintained plant is the goal. Follow CSU Extension defensible-space guidance and check with your local fire district before planting in the wildland-urban interface.
